Study Of The Protective Effects Of Autogenous Oxygenator CPB On Lung And It's Mechanisms

Objective To study the protective effects of autogenous oxygenator cardiopulmonary bypass on lung and it's mechanisms. Methods 12 adult mongrels (weight 13±1 kg) were randomly divided into two groups, 6 for experimental group, in that the dog's own lung is used as oxygenator;6 for control group in that the artificial lung (bubble oxygenator) is used as oxygenator. In experimental group, The CPB system was established by aorta and left atrium cannulation (for the left-heart bypass), pulmonary artery and right atrium cannulation (for the right-heart bypass). In control group, the CPB system was established by right atrium and aorta cannulation. The technique of myocardium protection and cardiac arrest were same in both groups. CPB was controlled running for 1 hour in both groups. In experimental group, the lung ventilation were kept during The lung tissue were sampled at the time of pre- CPB and 60th min after aotic off-clamping to test maleic dialdehyde(MDA )and superoxid dismutase(SOD) in both groups. The blood samples were collected at the time point of pre-operation, and 5th min,60th min of post aotic off-clamping to detect the TXA2 and PGI2 in both groups. The blood samples were also collected at the time point of pre-operation, 30th min of aotic on-clamping, and 5th min, 60th min, 120th min ,240th after declamping to detect the plasma concentration of IL-6, IL-8,TNF-α . Results The MDA of lung tissue after CPB were higher than pre-CPB in both groups, but it was not significantly higher in experimental group compared with controlled group (P<0.05).The SOD activity of lung tissue after aotic off-clamping were lower than pre-CPB in both groups, but it was not significantly lower in experimental group compared with controlled group (P<0.05). The levels of TXA2, PGI2 and the ratio of TXA2 and PGI2 after aotic off-clamping were higher than pre-CPB in both groups, but The levels of TXA2, the ratio of TXA2 and PGI2 were not significantly higher in experimental group compared with controlled group (P<0.05). The plasma level of IL-6, IL-8, TNF-αafter aotic off-clamping were higher than pre-CPB in both groups, but it was not significantly higher in experimental group compared with control group (P<0.05). Conclusion SIRS and ischemia-reperfusion of the lung play a main role on lung injury after CPB. The autogenous oxygenator CPB technique could decrease lung injury of post-CPB, so ,it may have good lung protection effects. The possible mechanisms is that the autogenous oxygenator CPB technique could inhibit SIRS and avoid theischemia-reperfusion of the lung.